The role of HCG increment in the 48h prior to methotrexate treatment as a predictor for treatment success

Abstract

Objective: To evaluate the role HCG change in the 48h prior to methotrexate treatment as a predictor for treatment success.

Study design: Medical records of all women who were diagnosed with ectopic pregnancy between January 2001 and June 2013 were reviewed. Four hundred and nine patients received methotrexate due to ectopic pregnancy. The "single dose" methotrexate protocol with 50mg/m² was administered to patients with progressing ectopic pregnancy. HCG levels in days 1, 4 and 7 were used to evaluate methotrexate treatment success. The percentage of HCG change in the 48h prior to methotrexate treatment was compared between patients who were successfully treated and those who failed treatment with methotrexate.

Results: Single dose methotrexate was successful in 309 patients (75.4%, success group). The medians of HCG change in the 48h prior to methotrexate administration were significantly higher in the "failure group" (21% vs. 4%, p<0.01). In a logistic regression analysis, the of HCG percent increment prior to methotrexate administration was shown to be an independent predictor for treatment outcome. Receiver operator characteristic curve for HCG percent change was 0.751, at a cutoff value of HCG increment <12% the positive predictive value for treatment success reached 86%.

Conclusions: Percentage of HCG increment in the 48h prior to methotrexate administration is an independent predictor for methotrexate treatment success. HCG increment <12% prior to methotrexate treatment is a good predictor for treatment success.

Keywords: Ectopic pregnancy; Human chorionic gonadotropin; Methotrexate.